<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>

    <!-- 
        hr 水平线
        br 强制换行   --- 不建议使用
     -->



    <!-- <hr /> -->
    <hr>

    hello
    <br>
    world

</body>

</html>